fix(slr): handle IsNotFound when deleting VIP CRD in handleDelSwitchLBRule

When multiple SLR controllers process deletion for SLRs sharing the same
subnet (via the fallback path), both may attempt to delete the same VIP
CRD. The second deletion gets an IsNotFound error, which previously caused
an unnecessary error and retry loop.

Signed-off-by: Mengxin Liu <liumengxinfly@gmail.com>
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: oilbeater

pkg/controller/switch_lb_rule.go

@@ -297,7 +297,7 @@ func (c *Controller) handleDelSwitchLBRule(info *SlrInfo) error {
 
 		if len(lbhcs) == 0 {
 			err = c.config.KubeOvnClient.KubeovnV1().Vips().Delete(context.Background(), vip, metav1.DeleteOptions{})
-			if err != nil {
+			if err != nil && !k8serrors.IsNotFound(err) {
 				klog.Errorf("failed to delete vip %s for load balancer health check, err: %v", vip, err)
 				return err
 			}